Builds / RTX 3090 24 GB
RTX 3090 at 250 W: Qwen3.8 27B, llama.cpp 40.6 vs patched vLLM + MTP 129.8 tok/s
Last updated:
- GPU(s)
- RTX 3090 24 GB
Amazon · eBay (used) · Newegg - VRAM / unified memory (GB)
- 24
- CPU
- not stated
- Motherboard
- not stated
- RAM
- not stated
- PSU
- not stated
- Other
- Test rig has two RTX 3090s; figures below are single-card unless noted. 250 W power cap, thinking disabled; driver 580.173; figures are the log's canonical single-card table (mean of 5 runs)
- Reported total cost
- not stated
- Power
- 250 W cap
Measured speed (generation tokens/sec)
| Model | Quant | Engine | tok/s | Prompt processing (tok/s) | Details |
|---|---|---|---|---|---|
| Qwen3.8 27B | UD-Q4_K_XL (GGUF) | llama.cpp, tuned | 40.6 | not stated | ⚡ spec-decode (MTP n=1)context: ~55-token prompt📏 Mean of 5; 42.6 at ~1K prompt; 27.6 with out-of-box defaults |
| Qwen3.8 27B | AutoRound W4A16 | vLLM (stock) | 32.6 | not stated | context: ~55-token prompt📏 Mean of 5, no speculation; 32.8 at ~1K prompt |
| Qwen3.8 27B | AutoRound W4A16 | vLLM (patched) | 129.8 | not stated | ⚡ spec-decode (MTP k=4)context: ~55-token prompt📏 Mean of 5, acceptance 0.764; 167.8 at ~1K prompt. Stock vLLM + MTP k=4 did 66.5 / 85.6 |
| Qwen3.8 27B | UD-Q4_K_XL (GGUF) | llama.cpp llama-bench, 1 GPU at 350 W | 38.8 | 1,027 @ 512-token prompt est. TTFT @8k ≈ 8.0 s (calculated from measured prefill) | context: tg128📏 llama-bench, f16 KV, 350 W (q8_0 KV: 38.7 tg, 1,275 pp512) |
Prompt processing = prefill speed (how fast the prompt is read) as reported by the source, with the prompt length it was measured at; blank = the source does not report it. est. TTFT @8k is calculated from the measured prefill speed (8,192 ÷ prefill tok/s), shown only when prefill was measured on a prompt of 512+ tokens. It is not a measurement and ignores load time and caching. measured TTFT is the source's own time-to-first-token. Why prefill matters for coding assistants.
Public measurement log for Qwen3.8 27B on RTX 3090. Patched vLLM + DFlash2 k=7 reached 145.7 (~55 prompt) / 212.1 (~1K) tok/s. Two cards with llama.cpp layer split: 42.6 tg128 / 1,391 pp512 at 350 W (a second card buys +35% prefill, +10% decode). The log's Flash-Next run uses IQ3_S, below Q4, so it is not listed. Found via llamaperf (discovery only); numbers read at the original log on 2026-10-30.
Blank fields = not stated in the source. We never estimate build data; GPU street prices above are separately sourced and dated.
Quick answers: Can RTX 3090 run Qwen3.8 27B?